If Zoro didn't show any expression like puzzlement or suspicion, it was probably because Sanji had told him that Noctis had quite a bit of trouble with learning the names and descriptions of Oni Giri's dishes off of the menu - and not just the Japanese words. But he'd been able to memorize it once Sanji had explained everything out loud.
Zoro used a finger to tap above each word as he said it, still holding the cover so Noctis could see. "Little. Red. Riding. Hood." Then he gestured at the girl character. "This is her, the girl wearing the magical hooded cloak that a sympathizer Witch worked up for her. And this is the wolf that sniffs her out and stops her from poisoning everybody." Yeah, it was kid stuff. But it also had simple language and illustrations with clear clues about what was going on in the text of the story.